Welcome to a lunch seminar with Chris Evans, professor at the Centre for Ecology and Hydrology in Bangor, UK.
Agriculturally-drained peatlands account for ~2.5% of global CO2 emissions, and ~20% of CO2 emissions from agriculture and land-use. Agricultural drainage causes peat compaction, subsidence, increasing requirements for energy-intensive pumped drainage, and ultimately land degradation or abandonment. With growing recognition of these environmental costs, efforts are being made to re-wet former agricultural peatlands.
In the UK, upland bogs that were ditched to support grazing in the 20th century are now being re-wetted. In the lowlands, however, most organic soils remain drained. Fully re-wetting this highly productive land would have major economic and societal impacts, and risk exporting emissions from food production to other countries. In SE Asia, socio-economic challenges are even more acute, with plantation agriculture on coastal peat supporting the livelihoods of millions of people. Consequently, any plan to reduce agricultural peatland emissions needs to either maintain existing income, or develop alternative income streams.
Efforts are now being made to develop high water table (paludiculture) alternatives to drainage-based agriculture, but these cannot yet be implemented commercially at scale. Despite the urgent need to achieve 'net zero' emissions under the Paris Agreement, it seems likely that many peatlands will remain under conventional agriculture for the foreseeable future, making it essential that measures are developed, tested and implemented to reduce emissions from these areas.
This presentation will evaluate the extent to which peatland emissions can be mitigated by changes in agricultural management, based on data from the UK, SE Asia and elsewhere. It will consider the challenges, opportunities, trade-offs and co-benefits of emissions mitigation, including impacts on subsidence, drainability and agricultural lifetime. Based on a synthesis of flux measurement data, the potential to mitigate global emissions by raising water levels in agricultural peatlands will be shown to be significant.
The presentation will also consider the challenges for capturing mitigation measures in national emissions inventories, and opportunities for improved monitoring by Earth Observation data.